The present invention relates to a lancet device, by which a lancet can be displaced along a piercing path to generate a piercing wound in a skin surface, in particular to obtain bodily fluid for diagnostic purposes, comprising a lancet drive having drive means for generating a drive force for a piercing movement of the lancet along the piercing path in the direction toward the skin surface.
Furthermore, the present invention relates to a method for generating a piercing wound in a skin surface using a lancet, in which the lancet is accelerated along a piercing path using a drive force generated by a drive spring in the direction toward the skin surface.
Lancet devices are required, for example, by diabetics, who have to check their blood sugar level frequently to be able to keep it within specific setpoint limits by insulin injections. Extensive scientific experimentation has proven that a dramatic reduction of the most severe long-term complications of diabetes mellitus (such as retinopathy with resulting blinding of the patient) may be achieved using an intensive treatment having at least four analyses per day.
For users of lancet devices, on one hand the most low-pain piercing possible and on the other hand the simplest possible operation and ability to handle the lancet device used are of great significance.
A requirement for low-pain piercing is the most rapid possible piercing movement having a short dwell time of the lancet in the skin. The use of drive springs has proven itself in the prior art for a correspondingly strong acceleration of the lancets. A disadvantage of lancet devices of this type is that manually tensioning the drive springs after completed piercing is cumbersome for many users. This is true in particular for people whose manual dexterity is restricted by age or illness.
A lancet device in which the drive spring is automatically tensioned by an electric motor does offer increased user comfort in this regard, but has the disadvantage of being larger and heavier because of the electric motor. A lancet device having an integrated electric motor therefore represents a burden for the user, who has to carry it around continuously for frequent measurements. In addition, the production costs are significantly increased by an electric motor.
Furthermore, lancet devices are known in the prior art in which the drive force is generated electromagnetically using a coil. Lancet devices of this type are disclosed, for example, in WO 02/100460 A2 and U.S. Pat. No. 6,364,889 B1. To be able to cause a sufficiently rapid piercing movement for a low-pain piercing using electromagnetic lancet drives of this type, strong magnetic fields must be generated. This requires that relatively strong electric currents flow through the drive coils used, which may be generated not at all or only with great effort in a small, compact handheld device. Electromagnetic lancet drives have therefore not been able to succeed against mechanical drives having drive springs up to this point.